Software-Defined Networking and Network Functions Virtualisation has brought a revolution within the telecom market landscape. Initial proof-of-concept prototypes for NFV-enabled solutions are being developed at the same time SDN models are identified as the futures solutions within the telecom realm. We provide in this article an overview of the SDN/NFV technologies over optical networks, as well as we provide the first formalisation model for the virtual network function complex scheduling problem. The article aims at being used as starting point in order to optimally solve the scheduling problem of virtual network functions that compose network services to be provisioned within the SDN paradigm.

This article focuses on planning and replanning of virtual infrastructures over optical cloud infrastructures comprising integrated optical network and IT resources. This concept has been developed in the context of the European project GEYSERS. GEYSERS has proposed a novel multi-layer architecture, described in detail, that employs optical networking capable of provisioning optical network and IT resources for end-to-end cloud service delivery. The procedures required to perform virtual infrastructure planning and replanning at the different architecture layers are also detailed. An optimization scheme suitable to dynamically plan and replan virtual infrastructures is presented and compared to conventional approaches, and the benefits of dynamic replanning are discussed and quantified. The final project demonstration, focusing on planning, replanning, and dynamically establishing virtual infrastructures over the physical resources, is presented, while some emulation results are provided to further evaluate the performance of the GEYSERS solution.

This work describes a novel approach for the reduction of energy consumption in data centres (DCs) that will yield benefits both in terms of running costs and its environmental impact. The method is based on the introduction of collaborative interactions and flexibility clauses in contracts between all the DC ecosystem entities. The included entities are all the actors along the energy
production–consumption chain, from the energy provider to the Information Technology customer. The collaborative approach also integrates the interaction between federated DCs. In this paper, we find a detailed description of the architecture that enables interaction between the DC ecosystem parties, which is designed to be progressively deployed, allowing traditional and ‘greened’ services to coexist, and without modification of the existing DC automation and framework systems.

One of the main challenges of network virtualization is the virtual network embedding problem (VNE) that consists of mapping virtual network demands in physical network resources. VNE can be decomposed into two stages: virtual node and virtual link mapping. In the first stage, each virtual node is mapped to a suitable node in the physical network whereas the second stage is in charge of mapping the links connecting virtual nodes to paths in the physical network that suit the virtual network demands. In this paper we propose the utilization of a mathematical multi-constraint routing framework called "paths algebra" to solve the virtual link mapping stage. Paths algebra provides the flexibility to introduce an unlimited number of linear and non-linear constraints and metrics to the problem while finding all the eligible paths in the physical network to perform the virtual link mapping resulting in better and more flexible embeddings

One of the main challenges of network virtualization is the virtual network embedding problem (VNE) that consists of mapping virtual network demands in physical network resources. VNE can be decomposed into two stages: virtual node and virtual link mapping. In the first stage, each virtual node is mapped to a suitable node in the physical network whereas the second stage is in charge of mapping the links connecting virtual nodes to paths in the physical network that suit the virtual network demands.
In this paper we propose the utilization of a mathematical multi-constraint routing framework called “paths algebra” to solve the virtual link mapping stage. Paths algebra provides the flexibility to introduce an unlimited number of linear and non-linear constraints and metrics to the problem while finding all the eligible paths in the physical network to perform the virtual link mapping resulting in better and more flexible embeddings.

This paper presents a new approach to service
assignment in Data Centers (DC), relating it to a classical
combinatory problem called Bin Packing Problem and adding
the possibility of delay and collaboration with users and energy
providers. This possibility proves to reduce in much the energy
consumption of the DC as well as the CO2 emissions.

Network virtualization is recognized as an enabling technology for the future Internet. It aims to overcome the resistance of the current Internet to architectural change. Application of this technology relies on algorithms that can instantiate virtualized networks on a substrate infrastructure, optimizing the layout for service-relevant metrics. This class of algorithms is commonly known as "Virtual Network Embedding (VNE)" algorithms. This paper presents a survey of current research in the VNE area. Based upon a novel classification scheme for VNE algorithms a taxonomy of current approaches to the VNE problem is provided and opportunities for further research are discussed.

Demand Response is a mechanism used in power
grids to manage customers’ power consumption during critical
situations (e.g. power shortage). Data centres are good candidates
to participate in Demand Response programs due to their high energy
use. In this paper, we present a generic architecture to enable
Demand Response between Energy Provider and Data Centres
realised in All4Green. To this end, we show our three-level
concept and then illustrate the building blocks of All4Green’s
architectural design. Furthermore, we introduce the novel aspects
of GreenSDA and GreenSLA for Energy Provider–Data centre
sub-ecosystem as well as Data centre–IT Client sub-ecosystem
respectively. In order to further reduce energy consumption and
CO2 emission, the notion of data centre federation is introduced:
savings can be expected if data centres start to collaborate by
exchanging workload. Also, we specify the technological solutions
necessary to implement our proposed architectural approach.
Finally, we present preliminary proof-of-concept experiments,
conducted both on traditional and cloud computing data centres,
which show relatively encouraging results.

Network virtualization is recognized as an enabling technology for the future Internet. It aims to overcome the resistance of the current Internet to architectural change and to enable a new business model decoupling the network services from the underlying infrastructure. The problem of embedding virtual networks in a substrate network is the main resource allocation challenge in network virtualization and is usually referred to as the Virtual Network Embedding (VNE) problem. VNE deals with the allocation of virtual resources both in nodes and links. Therefore, it can be divided into two sub-problems:
Virtual Node Mapping where virtual nodes have to be allocated in physical nodes and Virtual Link Mapping where virtual links connecting these virtual nodes have to be mapped to paths connecting the corresponding nodes in the substrate network. Application of network virtualization relies on algorithms that can instantiate virtualized networks on a substrate infrastructure, optimizing the layout for service-relevant metrics. This class of algorithms is commonly known as VNE algorithms. This thesis proposes a set of contributions to solve the research challenges of the VNE that have not been tackled by the research community. To do that, it performs a deep and comprehensive survey of virtual network embedding. The first research challenge identified is the lack of proposals to solve the virtual link mapping stage of VNE using single path in the physical network. As this problem is NP-hard, existing proposals solve it using well known shortest path algorithms that limit the mapping considering just one constraint. This thesis proposes the use of a mathematical multi-constraint routing framework called paths algebra to solve the virtual link mapping stage. Besides, the thesis introduces a new demand caused by virtual link demands into physical nodes acting as intermediate (hidden) hops in a path of the physical network. Most of the current VNE approaches are centralized. They suffer of scalability issues and provide a single point of failure. In addition, they are not able to embed virtual network requests arriving at the same time in parallel. To solve this challenge, this thesis proposes a distributed, parallel and universal virtual network embedding framework. The proposed framework can be used to run any existing embedding algorithm in a distributed way. Thereby, computational
load for embedding multiple virtual networks is spread across the substrate network Energy efficiency is one of the main challenges in future networking
environments. Network virtualization can be used to tackle this problem by sharing hardware, instead of requiring dedicated hardware for each instance. Until now, VNE algorithms do not consider energy as a factor for the mapping. This thesis introduces the energy aware VNE where the main objective is to switch off as many network nodes and interfaces as possible by allocating the virtual demands to a consolidated subset of active physical networking equipment. To evaluate and validate the aforementioned VNE proposals, this thesis helped in the development of a software framework called ALgorithms for Embedding VIrtual Networks (ALEVIN). ALEVIN allows to easily implement, evaluate and compare different VNE algorithms according to a set of metrics, which evaluate the algorithms and compute their results on a given scenario for arbitrary parameters.

Energy consumption of network operators can be minimized by the dynamic and smart relocation of networking resources. In this paper, we propose to take advantage of network virtualization to enable a smart energy aware network provisioning. The virtualization of networking resources leads to the problem of mapping virtual demands to physical resources, known as Virtual Network Embedding (VNE). Our proposal modifies and improves exact existing energy aware VNE proposals where the objective is to switch off as many network nodes and interfaces as possible by allocating the virtual demands to a consolidated subset of active physical networking equipment. As exact energy efficient VNE approaches are hard to solve for large network sizes and have an adverse effect in the number of successful embeddings, an heuristic approach to reconfigure the allocation of already embedded virtual networks, minimizing the energy consumption, is also proposed.

Current Internet has become an essential communication infrastructure, not only for information transfer but also as a key component of social infrastructures, such as e-government, energy/traffic controls, finance, learning, health, etc. Even though the Internet has evolved towards high-bandwidth network architectures offering transparent transport services for fixed and mobile applications, its future depends on how it is going to cope with several concerns on different aspects such as scalability, ubiquity, security, robustness, mobility, heterogeneity, Quality of Service (QoS), re-configurability, context-awareness, manageability, data-centric, economics, etc. This paper exposes the approaches proposed in the Spanish Government funded research project tin2010-20136-c03 to overcome identified drawbacks of the current internet, such as energy efficiency, network ossification, heterogeneity of information and coexistence of optical and wireless networks. In order to do so, two technologies have been identified as potential solutions to face some of these problems: i) Media Independence and ii) Virtualization. On the one hand, Media Independence enables the decoupling of the control plane from the physical technology specificities, by introducing an abstract control API to configure, monitor and command the physical interface. On the other hand, network virtualization strategies allow the partition of electrical and optical network infrastructures into multiple parallel, dedicated virtual networks for a physical infrastructure sharing purpose, and enables the creation of overlay networks spanning multiple technologies and realms, hence being a very useful tool for context-aware service composition.

One of the main challenges of network virtualization is the mapping of virtual network demands to physical network resources, commonly known as the virtual network embedding (VNE) problem. This paper introduces DPVNE, a distributed, parallel and generic VNE framework. DPVNE can be used 1) to run various cost-reducing embedding algorithms 2) in a distributed way. Thereby, computational load for embedding multiple virtual networks is spread across the substrate network reducing workload of individual nodes and 3) enabling the embedding of multiple virtual networks in parallel. DPVNE, in contrast to existing distributed algorithms, 4) achieves lower message overhead and, despite of being distributed, 5) keeps embedding costs comparable to those of centralized approaches.

In recent years, the emergence of the cloud computing has increased the need of resources to support cloud-based services. Therefore, the role of the data centers has become essential. Following the growing of services, the power consumption has increased dramatically, while the need for energy savings and CO2 reduction has become a requirement for a sustainable world.
The All4Green project fosters collaboration between energy providers (EP), data centers (DC) and customers/end users (EU) in order to provide energy sav-ings and CO2 emissions reduction. In this architecture, the contract binding EPs and DCs includes flexibility terms in order to allow the collaboration in the form of discounts that can be transferred also to DC customers, if they are willing to collaborate.

This paper describes how eco-motivated extensions added to the traditional SLA concept can provide levels of flexibility in the data centre management that enable the data centre to reduce the energy consumption, improve the environmental footprint and lower internal costs. A close collaboration with both the IT customer and the data centre’s energy provider are key to this approach which is formalized by means of the GreenSLA concept building on the three main components: Flexibility, GreenKPIs and collaboration. Performance decisions regarding the energy consumed by the services are taken and translated to actions to be executed to save energy while at the same time guaranteeing the contract agreements.

Network virtualization has emerged as a solution for the Internet inability to address the required challenges caused by the lack of coordination among Internet service providers for the deployment of new services. The allocation of resources is one of the main problems in network virtualization, mainly in the mapping of virtual nodes and links to specific substrate nodes and paths, also known as the virtual network embedding problem. This paper proposes an algorithm based on optimization theory, to map the virtual links and nodes requiring a specific demand, looking for the maximization of the spare bandwidth and spare CPU in the substrate network, taking into account the CPU demanded by the hidden hops when a virtual link is mapped. The components of the virtual networks (nodes and links) that do not ask for an specific demand are then allocated following a fairness criteria

Waste of energy due to over-provisioning and overdimensioning
of network infrastructures has recently stimulated
the interest on energy consumption reduction by Internet Service
Providers (ISPs). By means of resource consolidation, network
virtualization based architectures will enable energy saving. In
this letter, we extend the well-known virtual network embedding
problem (VNE) to energy awareness and propose a mixed
integer program (MIP) which provides optimal energy efficient
embeddings. Simulation results show the energy gains of the
proposed MIP over the existing cost-based VNE approach.

The time for an all-optical network is already here. The huge capacity of the optical resources, in backbones,
distribution and access networks cannot be completely used by current services. The remainders can be used
under the deployment of new models for service provisio
ning. Network virtualizati
on is considered as a serious
candidate to enable the flexibl
e provision of services in the future Internet. This paper introduces a framework to
enhance network virtualization allocati
on in optical networks. To
increase resources utilization efficiency, a new
layer above virtualized elements is introduced to map the
demands over the resour
ces and infrastructures. For
that layer, a strategy based on a resource squa
tting model is presented, modeled and analyzed.

Network virtualization is recognized as an enabling technology for the Future Internet that overcomes network ossification. However, it introduces a set of challenges. In any network virtualization environment, the problem of optimally mapping virtual demands to physical resources, known as virtual network embedding (VNE), is a crucial challenge. This paper analyses the behaviour of the main algorithms proposed to solve VNE by means of the ALEVIN framework. The VNE algorithms are evaluated with regard to appropriate metrics such as: cost, revenue, and virtual network acceptance ratio. We also analyse the impact of the recently introduced hidden hop demand concept
in the performance of the VNE algorithms.

Network virtualization is recognized as an enabling technology for the Future Internet that overcomes network ossification. However, it introduces a set of challenges. In any network virtualization environment, the problem of optimally mapping virtual resources to physical resources, known as virtual network embedding (VNE), is a critical challenge. Several algorithms attempting to solve this problem have been proposed in literature, so far. However, comparison of existing and new VNE algorithms is hard, as each algorithm focuses on different criteria. To that end, the VNREAL project introduces ALEVIN, a framework to compare different algorithms according to a set of metrics, easily incorporate new VNE algorithms, and evaluate these algorithms on a given scenario for arbitrary parameters.

This paper introduces a framework to enhance network virtualization allocation in optical networks. A new control plane approach for the new generation of electrical and optical networks technologies is presented. To
increase resources utilization efficiency, a new layer above virtualized elements is introduced in order to take into account the demands in order to control the resources and infrastructures below. For that layer, a strategy based on a resource squatting model is presented.

Network virtualization is recognized as an enabling technology for the Future Internet. Applying virtualization of network resources leads to the problem of mapping virtual resources to physical resources, known as “Virtual Network Embedding” (VNE). Several algorithms attempting to solve this problem have been discussed in the literature, so far. However, comparison of VNE algorithms is hard, as each algorithm focuses on different criteria. To that end, we introduce a framework to compare different algorithms according to a set of metrics, which allow to evaluate the algorithms and compute their results on a given scenario for arbitrary parameters.

This paper presents the testbed definition, implementation and trials of a new strategy for traffic autoprovisioning for MPLS and IP/DiffServ. This is the proof of concept of a new scenario for traffic engineering, for selfconfiguring control and end-to-end quality of service management by means of a tool based on Web Services. The system is structured in 3 layers: A Graphical User Interface, a Network Elements layer (an interface to physical devices) and, in the middle, a Network Management System layer, where decisions about admission, load balancing, path selection, rerouting and bandwidth allocation per class are taken. The system includes Dynamic Resource Allocation (DRA) and Background Monitoring System (BMS) modules to globally manage network resources. The so-called Squatter and Legalization mechanisms are introduced as novelties added to traffic engineering. Those strategies permit the use of part of the available resources from other classes only while unused by the class owning them. The trials hav validated the management system, using Cisco routers.

The pervasive distribution of digital devices (e.g., laptops, mobile phone, digital camera, music players, RFID, sensors, smart cards) will create a large distributed computational and networking environment that will foster the evolution towards ecosystems of resource, services and data. Dynamicity and ubiquity of said future environments pose new challenges and requirements that current infrastructures cannot meet. Several limitations have to be overcomed, for instance: low flexibility and scalability, missing optimized cross-layer/cognitive (and cross-domain) resources allocation, limited potentialities of fostering new business models and above all a brittle integration of IT and network solutions/technologies.
This paper proposes a systemic design to develop a future network architecture overcoming said limitations. Architecture is based on three main decentralised planes: the Knowledge Plane (KP), the Network Control Plane (NCP) and the Resource Control Plane (RCP). The three planes are implemented a distributed way and interact with each other (through a signalling overlay) for the allocation and management of virtual (communication, storage and processing) resources in overlay networks: novelty stands in coupling some enabling technologies with the creation and use of a cross-layer network knowledge. Paper also presents, as an example, some simulation results showing the optimal allocation of resources for the proposed architecture. Eventually, recommendations and future work conclude the paper.

This paper proposes a new paradigm and strategy for resource management in optical networks considering that
resources allocated to a user or service can be squatted in by third parties temporarily in order to provide support
for emergency situations or allocate traffic from different priorities that experience a sudden increase of
demanded resources in the network. We introduce the strategies of Soft Squatting and Hard Squatting.
Moreover, we propose a model and a preliminary evaluation for fibre infrastructure sharing in all-optical
networks using the proposed squatting strategies.

MANTICORE II follows the Infrastructure as a Service (IaaS) paradigm to enable National Research and Education Networks (NRENs) and other e-infrastructure providers to enhance their service portfolio by building and piloting the deployment of tools to provide infrastructure resources and IP networks as a service to virtual research communities. MANTICORE II is carrying out the following activities:
* Robust and modular implementation of IaaS management tools.
* Pilot software deployment and evaluation at HEAnet, NORDUnet and RedIRIS.
* Design and implement a simple yet powerful graphical interface for the IP Network Service.
* Study and simulate mechanisms to implement an infrastructure marketplace.
* Study business models and use cases for commercial services based on MANTICORE II principles.

In search of being able to offer better quality of service (QoS) in multiclass networks, a strategy that aims to allow resources between different classes of service (CoS) to be shared according to the
class’s needs and priority is proposed. The goal is to achieve an optimal use of the total bandwidth in a link. This paper presents shortly the proposed strategy and explains the “squatting” and “kicking” mechanisms. A model and simple results for performance to prove their utility are shown.

Bandwidth allocation is one of the main problems in network virtualization. Mechanisms to allocate bandwidth may avoid bottlenecked virtual links. This paper proposes a model based on optimization theory, to distribute the bandwidth among
virtual links looking for the minimization of the spare bandwidth in the substrate network.

This paper introduces a new strategy to provide QoS in IP/OBS networks, using Routing with Prioritization
Based on Statistics (RPBS). This proposal uses the feedback scheme in optical networks to provide statistical
knowledge with the objective of finding a suitable route for reach each destination from a specific source node,
with more chance of success. This yields a twofold outcome. First, the losses can be reduced due to the statistics.
Second, the delays are also reduced compare with other methods based on feedback scheme. These two
improvements allow better QoS provision, supporting class differentiation and more efficient resources
utilization. The benefits of this proposal are compared against existent alternatives by simulation.
Keywords: OBS, Statistical Routing, WDM, QoS Provision, JET, RPBS

Internet is becoming unable to overcome the challenges required by new services due to the lack of coordination among Internet service providers. This situation, frequently called network ossification, makes increasingly hard the deployment and the testing new network technologies. Network Virtualization has emerged as one solution of this problem. One network (substrate network), composed of physical
nodes (e.g. routers) interconnected by means of links, may be used to create several isolated virtual networks, formed by virtual nodes and links, sharing the physical resources of the substrate network. One of the known problems of network virtualization is the allocation of physical resources. An uncontrolled allocation of bandwidth might entail bottlenecked virtual networks. The main goal of this paper is to analyze the problem of bandwidth allocation among virtual networks and to show mechanisms to offer a fair bandwidth distribution.